Nature's Miracle solution works phenominally! you can get it anyt any pet store. just take the cushion covers off and throw it in the machine.. the cushions themselves, however seem to be the tricky part.
I agree that Natures Miracle works great! My Tiki has had issues with peeing on my couch & now that I have found that she has a terrible kidney infection, I'm hoping that I won't have to deal with it anymore. Just the other day, I took off the couch covers & washed them in the washer with a mix of Tide & vinegar. Then I took the pads, filled the bathtub with vinegar, water & Natures Miracle. It wasn't an easy task by any means, but I dipped the pads in the mix & scrubbed them really good. I have 2 couches & 8 pads to do, but I managed to get them pretty clean. The pads soak up water (or any liquid) REALLY well, so don't totally submerge them completely. It took 2 days for them to dry out with the fans on them none stop. Once they started to dry somewhat, I sprayed them down with Natures Miracle once again lightly. So far, I can not smell any urine smell what so ever & Tiki hasn't tried to mark them again. That's why it's so important to clean them right away or the cat will continue to use that spot over and over. It's also important to clean them very well...even if you can't smell urine anymore, the cat might. It's a lot of hard work, but it can be done.
Any enzyme based cleaner will work. Nature's Miracle is one of them. Some of the pet stores around us carry something called Simple Solutions. It doesn't matter the brand, just so long as it is an enzyme cleaner. Make sure you follow the directions closely, and they all seem to require a lot of shaking before use.
If your kitty continues to have problems with not peeing in the box, get him or her to the vet ASAP. 90% of the reason cats do not pee in the box are health-related, sometimes very serious, and the only symptom is that they don't use the box.